This invention relates generally to portable data collection and processing terminals for use in a Radio Frequency (RF) communication network, and, more specifically to portable terminals supporting a variety of RF transceivers and associated antenna systems. Additionally, this invention relates to methods in which a portable terminal gains access to the RF communication network.
In particular, portable data processing terminals have taken an increasingly significant role in business environments. For example, battery powered, hand-held data collection terminals are used extensively for inventory control in warehousing and merchandising operations. Other uses of such terminals include invoicing, delivery route management, order taking and return control operations--as might be found in automobile rental operations.
In many business environments, portable data processing terminals often need to communicate in real-time with other portable terminals, peripheral devices, work stations, and host computers. To meet such communication needs, a variety of mixed hard-wired and wireless communication networks with associated communication protocols have been developed, each addressing the specific requirements of a given business environment. In the process of such development, portable terminals have undergone tailoring of both hardware and software to fully support a specific communication network and associated protocol.
As a result of such tailoring, each type of portable data collection terminal is generally only capable of operating in a single type of business environment. Tailoring also results in unreasonable additional costs associated with developing, manufacturing, documenting, etc., each variety of portable data collection terminals.
More specifically, each portable data collection terminal includes a built-in radio transceiver. The built-in transceiver operates pursuant to only one of a variety of types of RF (Radio Frequency) communication characteristics, characteristics that are dictated per FCC (Federal Communication Commission) specification.
The choice of the type of radio transceiver, i.e., the type of RF communication characteristics, to build-in is based on the nature of the business environment. For example, a digital cellular radio might be chosen in a environment having great distances between the radio and the destination transceiver. Similarly, data might be exchanged using a single channel UHF (Ultra-High Frequency), direct-sequence spread-spectrum, or frequency-hopping spread-spectrum band. Each of these bands have particular characteristics which make them attractive for a given business environment, and each generally requiring a different transceiver.
After choosing the appropriate radio transceiver, an appropriate antenna must also be selected. Each type of transceiver often requires a different type of antenna based on the corresponding RF communication characteristics, the shape of the portable terminal, and the business environment at issue.
Thus, there is need to provide a portable data collection terminal capable of easily supporting any of the plurality of types of radio transceivers and associated antennas, minimizing needed modifications to the terminal's hardware and software design.
In addition, to support real-time access to a communication network, each portable data collection terminal needs to establish and maintain radio connectivity to the network. However, portable terminals must also address conflicting concerns of battery power conservation, i.e., maintaining connectivity places a substantial load on battery power. Moreover, the mobile nature of portable terminals also presents difficulties in maintaining connectivity. It would therefore be desirable to implement communication protocol techniques which address power saving and mobility concerns while providing virtually real-time access to the communication link.
Thus, an object of the present invention is to provide a modular hardware and software radio design for a portable data collection terminal which supports multiple types of radio transceivers and associated antennas.
It is also an object of the present invention to provide for the selection of ones of a plurality modular radio transceivers for use by a portable data terminal, the selection of which addresses the specific concerns of a given business environment.
Another object of the present invention is to provide for the selection of ones of a plurality of modular radio transceivers for use by a portable data terminal, wherein each modular transceiver selected isolates the data collection terminal from transceiver specific operations by providing hardware and software control over such functions.
A further object of the present invention is to provide a communication protocol which address power saving and mobility concerns while providing virtually real-time access to the communication link.
Another object of the present invention is to provide a communication protocol for use by a portable data collection terminal which minimizes transmission collisions while providing for virtually real-time access to the communication network.
Another object of the present invention is to provide a communication protocol for use by a portable data collection terminal which eliminates the need for random number generation and random back-off techniques.
A further object of the present invention is to provide an improved computer device apparatus for connecting a removable card type radio to a protected, interchangeable, environmentally sealed antenna which uses contacts located on the housing of the radio card.
An object of the present invention is to provide an improved antenna connector for use with radio cards which can be inserted into various computer devices.
An object of the present invention is to provide an antenna cap, for use with computer devices utilizing radio cards, which is reliable, economical and easy to use.
A further object of the present invention is to provide an antenna cap whereby an appropriate antenna will be connected to a radio card by selectively positioning the antenna contacts on the radio card.
Another object of the present invention is to provide an antenna cap whereby a radio card may simultaneously connect to and utilize more than one radio antenna, and where the radio card may contain more than one type of radio transceiver.
A further object of the present invention is to provide an improved antenna connector whereby an appropriate antenna(s) will be connected to a radio card by selectively positioning the antenna contacts on the radio card.
A further object of the present invention is to provide an improved apparatus which utilizes only one set of contacts on a radio card or modem card and uses a switching matrix to connect the radio card or modem card to the appropriate antenna or telephone line.
Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.